Wall ties and cavity insulation

What is a borescope inspection for cavity wall ties, and is it part of a Level 2?

A borescope inspection drills small holes and looks into the cavity with a camera to see the ties and the debris. A standard Level 2 does not include that. It is a further investigation when the visual clues suggest the ties may be failing.

Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.

What is the fuller explanation?

Visual clues include horizontal cracks in the mortar, a bulging outer leaf, and rusty stains. They are not proof of every tie’s condition. A Level 2 records those clues if they are visible and says if a specialist should look. Drilling the wall is outside the normal instruction, and it needs the owner’s consent.

If you commission a borescope survey, ask how many openings, which elevations, and whether the fee includes a written report with photographs. Prices vary with the number of holes and the access. Ask the firm. Do not treat a single hole at the front as a survey of the gable. The Property Care Association and similar specialists do this work. The home surveyor does not become that specialist by mentioning ties.

What should you ask your surveyor?

Which cracks or bulges did you see, and on which walls?
Are you recommending a borescope, or only noting that ties exist?
What would you expect a specialist to open that you did not?

What are the typical next steps?

Do not buy replacement ties on a hunch. Get the cavity looked at if the visual clues are real.
Agree the number of inspection holes in writing.
Ask the lender only after you have a specialist’s words, not on the phrase “ties possible”.

Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.

Also asked about this

Does one rusty tie mean the whole wall needs new ties?

Not from one photograph. The specialist should say how widespread the corrosion is. A single tie can be a local defect.

Will the holes be made good?

Ask for that in the quote. An inspection that leaves open holes is unfinished.